FARM BUILDINGS. 635 



an abundance of pure air. It is often astonishing to see how rapidly a person will recover as 

 soon as his strength will admit of his getting out to spend a considerable time in the open air. 

 It has been found by experiment that an adult man gives off, in breathing, from six to seven- 

 tenths of a cubic foot of carbonic acid in an hour while awake, and from five to six-tenths of 

 a cubic foot when asleep. Also that he inhales at least twenty cubic inches of air at each 

 breath, which, allowing twenty respirations per minute, is equal to fourteen cubic feet of air 

 passing through the lungs per hour. 



The air that is expelled from the lungs in breathing contains from 4 to 5 per cent, or 

 more of carbonic acid, and is saturated with moisture from the lungs. Besides the vapor 

 given off by the lungs, there is also that which escapes through the pores of the skin, which 

 is estimated to be in an adult person equal to from -fa to J of a pound per hour, which also 

 escapes into the surrounding air. These vapors, thus escaping from the body through breath 

 ing and perspiration, contain substances which are injurious, if taken into the system again, 

 and which are necessary to be removed at first, in order to maintain a healthy condition. One 

 of the functions or uses of breathing and perspiration is to remove them from the body. &quot;We 

 can, therefore, easily perceive how soon the air of a small and perfectly tight room would 

 become vitiated by even the presence of one individual, and also how important it is that the 

 effete waste matter once thrown off from the system, should not be taken into it again. This 

 can only be prevented by proper ventilation, which shall provide a sufficient supply of pure 

 air to be inhaled, instead of that which has been thus poisoned. 



In the construction of a house, one of the most important things to be considered is 

 providing suitable means for its proper ventilation. To permit of a suitable amount of fresh 

 air being introduced into a room, and thoroughly distributed without producing draughts 

 upon the occupants, should be the object in planning for this purpose. Volumes might be 

 written on the different methods that might be employed in ventilating buildings and the 

 arguments given to maintain them, but our space will admit of only a few general sugges 

 tions with respect to the subject. 



No change of air can be obtained in an apartment except when the inside air is either 

 warmer or colder than the air outside, or in other words, except there is a difference of tem 

 perature between the indoor and outdoor air. For this reason open windows will not prove 

 an effectual means of ventilation unless the air in the room is warmer or colder than the 

 atmosphere without. The old-fashioned fire-place furnished to our ancestors an admirable 

 means of ventilation, since it permitted the impure air to pass up the chimney, while pure air 

 could be admitted by windows or doors, or what would be better, through a tube or pipe 

 suitably arranged for the purpose of conveying it into the apartment. For this reason open 

 grates and stoves similarly constructed furnish better facilities for ventilating a room than 

 close, air-tight stoves. A considerable portion of warm air will, of course, also by this means 

 escape up the chimney, but the benefits to be secured by the improved condition of air in the 

 room will more than repay the extra expense of heating. 



The windows of a house should all be so arranged that they can be lowered at the top, as 

 well as raised at the bottom. Doors and windows should be freely opened in a house during 

 the summer, in order to permit the pure air from without to have free circulation through 

 the building. This cannot be well secured unless the windows or doors on opposite sides of 

 the room be opened, thus furnishing the means for the impure air to escape and the pure air 

 to enter. If no means are provided for the escape of the air already in the apartment the 

 outside air cannot be admitted, for nothing can ever be more than full, and we cannot force 

 air into a room already full. Windows should also be opened every few hours during the 

 winter, if no other means of ventilation are provided. 



The fire in every ordinary stove furnishes the means for the escape of some of the air of 

 the room by the draught produced, while fresh air from without finds entrance from about 



